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5. Function and application
5.1. Network element type
OPCOM3100-155 is suitable for network end access. It can provide STM-1, E1
and Ethernet access and can be configured as TM, ADM and REG.
1.
Terminal multiplexer (TM)
The main function of terminal multiplexer (TM) is multiplexing low speed E1
or Ethernet signal to high speed STM-1 SDH signal and demultiplexing
high speed STM-1 SDH signal to low speed E1 or Ethernet signal.
STM-1 optical
signal
E1 electrical signal/Ethernet
signal
Figure 5-1 TM network element type
2.
Add/Drop multiplexer (ADM)
Add/Drop multiplexer (ADM) is the most common network element type in
SDH network, it has both synchronous multiplexing function and digital cross
connection function, and can add/drop the tributary signal flexibly. For example
the access E1 signal can be multiplexed to both east STM-1 signal and west
STM-1 signal.
S T M - 1 o p t i c a l
s i g n a l
S T M - 1 o p t i c a l
s i g n a l
E 1 e l e c t r i c a l s i g n a l / E t h e r n e t s i g n a l
Figure 5-2 ADM network element type
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